Method of preventing yellowing in fabrics and garments

ABSTRACT

The invention relates to methods of preventing yellowing of textiles comprising polyurethane foam and at least one phenolic antioxidant by contacting the textile with at least one aryl alkyl sulfonic acid salt and to textiles obtained by such methods.

FIELD OF THE INVENTION

The invention concerns, inter alia., use of aryl alkyl sulfonic acidsalts to reduce yellowing caused by phenolic antioxidants in textilefabrics and garments.

BACKGROUND OF THE INVENTION

While polyurethane foam has been extensively utilized in the manufactureof brassiers and other garment parts, it has a disadvantage of yellowingas it ages. One reason for yellowing is the presence of phenolicantioxidants such as butylated hydroxyl toluene (BHT). Theseantioxidants can cause yellow color when exposed to environmentalnitrogen oxide (NOx) gases. Such gases can result from, for example, airpollution, tow motor emissions, and gas furnaces. The reaction ispromoted by alkaline conditions and retarded by acidic environments. Theformation of the yellow colored chromophores is reversible. The BHT canrevert to a colorless form if treated with an acidic rinse such asdilute acetic or citric acid. Some reports indicate that this yellowcolor is caused by the formation of 2,6-di-tert-butyl-1,4-quinonemethide. Because the color can be aesthetically unpleasing, methods ofavoiding such yellow coloring are need in the art.

SUMMARY OF THE INVENTION

In some embodiments are methods of preventing yellowing of textilesincluding polyurethane foam and at least one phenolic antioxidant bycontacting said textile with at least one aryl alkyl sulfonic acid salt.In some embodiments, the aryl alkyl sulfonic acid salt is of Formula l:

where R is an aryl group substituted with at least one C₃ to C₂₀ alkylgroup, such as a C₈ to C₁₆ alkyl group; and Z+ is a cationic counterion. Suitable Z+ ions include alkali metal cations and alkyl ammoniumsalts.

Examples of aryl alkyl sulfonic acid salts that are useful in someembodiments include adducts of dodecylbenzenesulfonic acid withN,N-bis(2-hydroxyethyl)-N-methyl-(z)-9-octadecene-1-aminium chloride, anadduct of dodecylbenzenesulfonate with 2-aminoethanol or an adduct ofdodecylbenzenesulfonate with 2,2,2-nitriltris(ethanol).

Some methods additionally comprising contacting said textile with acompound of Formula II:

where Ra and Rb are each, independently, C₁ to C₁₈ alkyl and M is K, Na,or Li.

In some embodiments, the aryl alkyl sulfonic acid salt is contacted withthe textile by applying a solution of aryl alkyl sulfonic acid salt tothe textile. Some solutions have a concentration 5-30 g/l of the arylsulfonic acid salt in an aqueous solution at pH 4-6. The solution can beapplied to the textile by any known method. These methods includeimmersing the textile is in the solution, spraying the solution onto thetextile, and padding the solution onto the textile.

Another aspect of some embodiments are articles including polyurethanefoam, at least one phenolic antioxidant, and at least one aryl alkylsulfonic acid salt. Some articles form a component of a brassiere.Suitable antioxidants and aryl alkyl sulfonic acid salts include thosedescribed herein. Some compositions additionally include a compound ofFormula II.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In some embodiments are methods for preventing yellowing of textilesincluding polyurethane foam and at least one phenolic antioxidant bycontacting the textile with at least one aryl alkyl sulfonic acid salt.

In some embodiments, the aryl alkyl sulfonic acid salt is of Formula l:

where R is an aryl group substituted with at least one C₃ to C₂₀ alkylgroup; and Z+ is a cationic counter ion. Examples of R groups are arylgroups substituted with at least one C₈to C₁₆ alkyl group.

Suitable Z+ ions include alkali metal cations. The alkali metals includelithium, sodium, and potassium. In some embodiments, sodium is chosen asthe alkali metal. Other suitable Z+ ions include alkyl ammonium salts.Some alkyl ammonium salts are of Formula III where Rc, Rd, Re, and Rfare each independently H or C₁ to C₁₆ optionally substituted alkyl andX— is a counter ion for the ammonium cation. Some suitable alkylammonium salts are tetralkyl ammonium salts. One suitable alkyl ammoniumsalts is ammonium chloride. Suitable X— anions include halogens,including chloride, bromide, and iodide.

One commercial product useful in the present invention is Cibafast® CTwhich is includes 2.5-5%—N,N-bis(2-hydroxyethyl)-N-methyl-(Z)-9-Octadecen-1-aminium chloride (ECno 242-332-0); 20-30%-Benzenenesulfonic acid, dodecyl-, compound with2-aminoethanol (1:1), and 20-30%-Benzensulfonicacid,dodecyl-, compound,with 2,2′,2″-nitrilotris (ethanol)(1:1).

Examples of useful aryl alkyl sulfonic acid salts include adducts ofdodecylbenzenesulfonic acid withN,N-bis(2-hydroxyethyl)-N-methyl-(z)-9-octadecene-1-aminium chloride, anadduct of dodecylbenzenesulfonate with 2-aminoethanol or an adduct ofdodecylbenzenesulfonate with 2,2,2-nitrilotris(ethanol). Examples ofcombinations of useful compositions with aryl alkyl sulfonic acid saltsinclude N,N-bis(2-hydroxyethyl)-N-methyl-(z)-9-Octadecen-1-aminiumchloride benzenesulfonic acid dodecyl-compound with 2-aminoethanol(1:1); benzenesulfonic acid dodecyl-compound with 2,2,2-nitrilotris(ethanol) (1:1); sulfuric acid mono(2-ethoylhexyl) ester, sodium salt;alkylbenzenesulfonic, triethanolamine salt; and combinations thereof.Commercially available compositions including aryl alkyl sulfonic acidsalts are available under the trade names Depicol LG available fromZschimmer and Schwarz, Cibafast® CT, available from Huntsman, Ultraphor®AUC-NY available from BASF, CHT-FASERSCHUTZ RPY SPEZ available from CHT,Umidol APY liq, available from Clariant, Levasalt AY available fromTanatex, Rucolan VG1 available from Rudolf Chemicals, and combinationsthereof.

Some methods additionally include contacting the textile with a compoundof Formula II:

where Ra and Rb are each, independently, C₁ to C₁₈ alkyl and M is K, Na,or Li. The compound of Formula II can be in the same solution as thecompound of Formula I or may be in a separate solution.

The aryl alkyl sulfonic acid salt compositions (the anti-BHTcompositions) may be added to polyurethane foam in any suitable manner.One useful process includes preparing a solution of about 0.1-60 g/litreequivalent to 0.01 to 6 g on weight of foam of the anti-BHT compositionin water. The solution may be made up slightly acid to neutral pH 4.0-7with any suitable acid such as citric acid or tartaric acid (anon-volatile organic acid). The solution may be applied to the foam bydipping, padding, spraying, or by combinations thereof. In the dippingprocess, the solution may be added to a trough, a roll of prepared foamis then passed over guide rollers and dipped through the solution anddried. In a padding application, the solution may be added to a tankthat is then added or metered into a trough foam is passed through guiderollers into the trough then through squeeze rollers the amount pickedup by the foam is controlled by the pressure applied by the mainrollers, the amount picked up can be measured by taking simple weightmeasurements before and after application, the formulation concentrationcan be adjusted to meet the efficiency of the pick-up in the trough. Ina spraying process, controlled spray units fed by storage tanks applythe anti BHT composition evenly over the surface of the foam.

The foam is then dried by any suitable method including air drying, byheated rollers, heated air through perforated drums, infrared dryers,and combinations thereof.

In some embodiments, the aryl alkyl sulfonic acid salt is contacted withthe textile by applying a solution of aryl alkyl sulfonic acid salt tothe textile. Some solutions have a concentration 5-30 g/l of the arylsulfonic acid salt in an aqueous solution at pH 4-6. In someembodiments, the compound of Formula II is present in an amount of 1-20g/l. The solutions are made by dissolving the arylalkyl sulfonic acidsalt and optionally the compound of Formula II in water by techniqueswell known to those skilled in the art. The water may be used as is orpurified prior to forming the solution.

In some embodiments, the phenolic antioxidant is2,6-di-tert-butyl-4-methylphenol, also known as butylated hydroxytoluene(BHT). This product is sold commercially as an antioxidant food additiveand in cosmetics, pharmaceuticals, jet fuels, rubber, petroleumproducts, and embalming fluid.

One or more antioxidants may be used in the combination with thetextiles of some embodiments. Suitable antioxidants include2,6-di-tert-butyl-4-methylphenol 2,6-di-tert-butyl-4-ethylphenol,2,4,6-tri-tert-butylphenol, 2,6-di-tert-butyl-4-hydroxymethylphenol,2,2′-methylenebis(4-ethyl-6-tert-butylphenol),2,2′-methylenebis(6-cyclohexyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-butylidenebis(3-methyl-6-tert-butylphenol),2,2′-methylenebis(4-methyl-6-tert-butylphenol),1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,4,4′-thiobis(3-methyl-6-tert-butylphenol),1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanate and1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanate. Amongst them,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethyl-benzyl) isocyanate,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanate,4,4′-butylidenebis(3-methyl-6-tert-butylphenol),1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene andcombinations thereof.

The solutions may additionally comprise additional compositions thatmight be useful to a particular application. Such compositions includesurfactants, stabilizers, other antioxidants (such as those that preventheat damage), softeners, finishes, and combinations thereof.

The solution can be applied to the textile by any known method. Thesemethods include immersing the textile in the solution, spraying thesolution onto the textile, and padding the solution onto the textile.

As used herein, the term “alkyl”, unless otherwise indicated, refers toboth straight- and branched-chain saturated aliphatic hydrocarbon groupshaving at least one carbon atoms, e.g., 1 to 18 carbon atoms.

The term “aryl” referrers herein to refer to an aromatic system , e.g.,of 6 to 14 carbon atoms, which may be a single ring or multiple aromaticrings fused or linked together as such that at least one part of thefused or linked rings forms the conjugated aromatic system. The arylgroups include but not limited to phenyl, naphthyl, biphenyl, anthryl,tetrahydronaphthyl, and phenanthryl.

Alkyl and aryl groups can be optionally substituted. One or moresubstituents may be utilized. Typical substituents include halogen, CN,OH, NO₂, amino, alkyl, cycloalkyl, alkenyl, alkynyl, alkoxy, aryloxy,substituted alkyloxy, alkylcarbonyl, alkylcarboxy, alkylamino, orarylthio.

In another embodiment are articles including polyurethane foam, at leastone phenolic antioxidant, and at least one aryl alkyl sulfonic acidsalt. Some articles may be included as components of a brassiere.Suitable antioxidants and aryl alkyl sulfonic acid salts include thosedescribed herein. Some compositions additionally include a compound ofFormula II.

Polyurethane is used in a wide variety of products such as for garmentsand in the automotive industry. The products that will benefit most fromthe treatment described in some embodiments are those products where thepolyurethane foam is visual, in other words, where yellowing of the foamis readily apparent. Examples of such uses of polyurethane foam includegarments such as brassieres and shoulder pads in ready to wear garments.

The features and advantages of the present invention are more fullyshown by the following examples which are provided for purposes ofillustration, and are not to be construed as limiting the invention inany way.

EXAMPLE

Test method:

Given the extensive acknowledgement of the problem concerning yellowingof polyurethane foam, Courtalds Textiles developed a test to determinethe potential of white or pastel textiles to yellow due to contaminationby sterically hindered phenols (phenolic antioxidants). This text hasbeen adopted by Marks and Spencer (a UK retailer) as well as by otherretailers/ garment makers as “Method C20B Elusive/Reversible Yellowing.”The textile sample to be tested is inserted between two layers of afolded sheet of paper impregnated with a solution of about 0.01% DTNP.The sandwich obtained is placed on a glass plate and covered with asecond glass plate. The assembly consisting of five (5) samples iswrapped airtight in polyethylene film free of BHT. The package is placedin a drying oven for 16 hours at 50° C. ±3° C. then removed and cooledto room temperature before unwrapping.

Since the color may fade on certain substrates, the degree of yellowingis immediately assessed with the gray scale for staining used for thedetermination of fastness (rating 1-5). A rating of 4-5 to 5 shouldensure complete protection against phenolic yellowing. A result of 4 isbelieved to be acceptable.

The foam samples were obtained under the trade name BULFAST availablefrom Recticel Belguim. The foam samples were BULFAST T35H/4 mmcompressed to 1 mm (35 kg/m³)—for harder firmer cups; BULFAST TO 51H /4mm compressed to 1 mm (51 kg/m³)—for breathable stretch/supportgarments; BULFAST TO 45F/4 mm-firm cup shape; BULFAST TO 45S /4 mm-softversion of 45F; BULFAST Texo M5-high light stability and improved NOx;Optical White S5180W-50 kg m³ easy to mold/reduced yellowing).

The Courtalds test was performed twice for each sample, once with theuntreated foam and once with a treatment described below:

Each sample of polyurethane foam containing BHT antioxidant wascontacted with Cibafast® CT by immersing the foam in a tray of a 5-30g/l aqueous solution of Cibafast® CT and water, neutral pH 4-7. The foamis removed from the solution and allowed to air dry.

For improved accuracy of the measurement, we have measured the CIE andGanz whiteness values as all the untreated samples do not meet thestandards by achieving a rating of 2.

The inventive articles each met the expectations set forth in theCourtalds test by achieving a rating of 4-5 to 5.

While there have been described what are presently believed to be thepreferred embodiments of the invention, those skilled in the art willrealize that changes and modifications may be made thereto withoutdeparting from the spirit of the invention, and it is intended toinclude all such changes and modifications as fall within the true scopeof the invention.

1. A method of preventing yellowing of textiles comprising polyurethanefoam and at least one phenolic antioxidant, said method comprisingcontacting said textile with at least one aryl alkyl sulfonic acid salt.2. The method of claim 1, wherein the aryl alkyl sulfonic acid salt isof the formula:

where R is an aryl group substituted with at least one C₃ to C₂₀ alkylgroup; and Z+ is a cationic counter ion.
 3. The method of claim 2,wherein R is aryl group substituted with at least one C₈ to C₁₆ alkylgroup.
 4. The method of claim 2, wherein Z+ is an alkali metal cation oran alkyl ammonium salt.
 5. The method of claim 1, wherein the aryl alkylsulfonic acid salt is an adduct of dodecylbenzenesulfonic acid withN,N-bis(2-hydroxyethyl)-N-methyl-(z)-9-octadecene-1-aminium chloride, anadduct of dodecylbenzenesulfonate with 2-aminoethanol or an adduct ofdodecylbenzenesulfonate with 2,2,2-nitriltris(ethanol), and combinationsthereof.
 6. The method of claim 1, wherein the textile comprises atleast two antioxidants.
 7. The method of claim 6, wherein saidantioxidant is 2,6-di-tert-butyl-4-methylphenol.
 8. The method of claim1, wherein said aryl alkyl sulfonic acid salt is contacted with saidtextile by applying a solution of aryl alkyl sulfonic acid salt to saidtextile.
 9. The method of claim 9, wherein said solution has aconcentration 5-30 g/l in an aqueous solution at pH 4-6.
 10. The methodof claim 9, where said textile is immersed in said solution.
 11. Themethod of claim 9, wherein said solution is applied to said textile byspraying said solution onto said textile.
 12. The method of claim 9,wherein said solution is applied to said textile by padding saidsolution onto the textile.
 13. The method of claim 1, additionallycomprising contacting said textile with a compound of the formula:

where Ra and Rb are each, independently, C₁ to C18 alkyl and M is K, Na,or Li.
 14. An article comprising polyurethane foam, at least onephenolic antioxidant, and at least one aryl alkyl sulfonic acid salt.15. The article of claim 14, where the aryl alkyl sulfonic acid salt iswherein the aryl alkyl sulfonic acid salt is of the formula:

where R is an aryl group substituted with at least one C₃ to C₂₀ alkylgroup; and Z+ is a cationic counter ion.
 16. The article of claim 15,wherein R is aryl group substituted with at least one C₈to C₁₆ alkylgroup.
 17. The article of claim 15, wherein Z+ is an alkali metal cationor an alkyl ammonium salt.
 18. The article of claim 14, wherein the arylalkyl sulfonic acid salt is an adduct of dodecylbenzenesulfonic acidwith N,N-bis(2-hydroxyethyl)-N-methyl-(z)-9-octadecene-1-aminiumchloride, an adduct of dodecylbenzenesulfonate with 2-aminoethanol or anadduct of dodecylbenzenesulfonate with 2,2,2-nitriltris(ethanol), andcombinations thereof.
 19. The article of claim 14 additionallycomprising a compound of the formula:

where Ra and Rb are each, independently, C₁ to C₁₈ alkyl and M is K, Na,or Li.
 20. The article of claim 14 that comprises a component of abrassiere.
 21. A brassiere comprising at least one foam component, saidfoam component comprising polyurethane foam, at least one phenolicantioxidant, and at least one aryl alkyl sulfonic acid salt.
 22. Thebrassiere of claim 21, wherein the aryl alkyl sulfonic acid salt iswherein the aryl alkyl sulfonic acid salt is of the formula:

where R is an aryl group substituted with at least one C₃ to C₂₀ alkylgroup; and Z+ is a cationic counter ion.